Cleansing implement and electrically powered dental cleansing device

ABSTRACT

The invention is directed to an electrically powered dental cleansing device (1) to which a cleansing implement (32) is fitted. In this manner, the cleansing implement (32) can be rotated about its longitudinal axis. The cleansing implement (32) is configured as an integrally formed part comprising a thin and elongate cleansing shaft (125). The cleansing shaft has at least one longitudinal edge and is provided with a plurality of serrations.

This invention relates to an electrically powered dental cleansingdevice comprising a cleansing implement which is rotatable about itslongitudinal axis by a motor provided in the dental cleansing device.

Such a dental cleansing device and a cleansing implement are known fromGerman Patent No. 1,011,116. This patent discloses a pencil mounted on ashaft coupled to a drive unit. The pencil is comprised of a plurality ofindividual hairs of a length dimensioned such that the pencil is taperedtowards a pointed free end. By means of the drive unit, the pencil canbe rotated about its longitudinal axis for performing a tooth cleaningfunction. However, because of the relatively large dimensions of thepencil, this implement is not suitable for interproximal cleaning.

From DE-OS 1,766,651 a device is known which can be used by dentists forgrinding off amalgam fillings, for example. For tooth treatment, thedevice comprises an instrument similar to a blade which can be caused toperform a lifting motion by a drive unit. To increase the abrasiveeffect, the instrument can be coated with additional particles asgrinding powder, for example. Considering, however, that the instrumenthas a width and thickness of several millimeters, this device is notsuited for cleaning interproximal spaces.

It is an object of the present invention to provide a dental cleansingdevice and a cleansing implement for an electrically powered dentalcleansing device which enables in particular the interproximal spaces tobe cleaned, which affords simple and secure manipulation, and which canbe introduced into the interproximal spaces with particular ease.

According to the present invention, this object is essentiallyaccomplished in that the cleansing implement is configured as anintegrally formed part comprising a thin, elongate cleansing shaft whichis flexible.

On account of the thin and elongate configuration of the cleansingshaft, the cleansing implement is also suitable for cleaning narrowinterproximal spaces. Because the flexible cleansing shaft is adapted tobe rotated about its longitudinal axis, it will automatically engagewithin the interproximal spaces. In the cleansing implement of thepresent invention, this automatic engaging action largely eliminates thepossibility of injury otherwise occurring, for example, by impropermanual insertion of dental floss into tight interdental spaces for lackof knowledge or experience of its user. Because the complete cleansingimplement is formed as an integral part, economy of manufacture isachieved.

In a feature of the present invention, the cleansing shaft includes atleast one longitudinal edge. In use of the cleansing implement, thislongitudinal edge wipes off plaque from the user's teeth.

According to a further feature of the present invention, the cleansingshaft has an essentially square cross-section. As a result, the fourlongitudinal edges thus provided on the cleansing shaft make it possibleto achieve an improved cleaning effect.

Advantageously, the sides of the cleansing shaft of essentially squarecross-section have a length of 0.3 mm, approximately.

In a further feature of the present invention, a plurality of serrationsproject from the surface of the cleansing shaft. When the cleansingimplement is in use, these serrations serve the function of removingplaque from the user's teeth. It will be understood that the cleansingshaft may also be provided with stiffening ribs on its longitudinalsides which act as cleaning edges.

The cleansing shaft has preferably a length of between 10 and 15 mm. Thethickness of the cleansing shaft is preferably in the range from 0.1 to0.5 mm. The height and width of the serrations are preferably within therange of 0.1 and 0.3 mm.

In an advantageous further feature of the present invention, thecleansing implement is made of a plastics material. This allows economyof manufacture of the cleansing implement.

By providing the cleansing shaft with an unbalance by designedaccumulation of material, the cleansing shaft is deflected from its restposition in the manner of a whip during rotation, which has a highlybeneficial effect on the cleaning of the interproximal spaces.

In a still further feature of the present invention, the cleansingimplement is adapted to be a push-fit on the dental cleansing device.This enables the user to substitute a new cleansing implement of likeconstruction for a worn cleansing implement with ease and speed.

In an extremely advantageous feature, the cleansing implement is made ofpolyester elastomer or a material exhibiting like or similar properties.owing to the special properties of this material, the shaft of thecleansing implement can be bent by an angle of up to 180 degreesparticularly also during use, without the risk of shaft rupture. For onething, this practically precludes the possibility of injury by aruptured shaft, and for another thing, it enables the teeth to becleaned also in the subgingival region even when the shaft is bent by180 degrees, in which event the cleaning function is mainly performed bythe bent area of the bent shaft. Utilizing this material for thecleansing implement or also for the shaft itself results in improvedmanipulation also for the inexperienced user, in addition to enhancingthe cleaning effect.

The present invention also relates to an electrically powered dentalcleansing device in which an elongate, thin and flexible cleansingimplement is adapted to be coupled to a drive shaft received in a handlesection and is rotatable about its longitudinal axis.

Simple and secure manipulation of the dental cleansing device isessentially ensured in that in the dental cleansing device incorporatingthe features initially referred to an attachment is adapted to bepush-fitted to the handle section, and that the cleansing implement isslidably received in the attachment.

By slidably accommodating the cleansing implement in the attachment, thepossibility is provided to optimally adapt the dental cleansing devicefor its individual uses. Thus, the cleansing implement is slidable outof the attachment when a user desires to use the dental cleansing devicefor interproximal cleaning. By contrast, when the dental cleansingdevice is not in use, the cleansing implement can be pushed back intothe interior of the attachment, thereby obviating the possibility ofcontamination of, or damage to, the cleansing implement. The cleansingimplement thus also meets hygienic demands, in addition to being usablefor a prolonged period. For example, when it is desired to take thecleansing implement on trips, it is ensured that the cleansing implementis not contaminated or damaged by other objects or, conversely, that thecleansing implement does not contaminate or damage these objects. Whenthe cleansing implement is worn after prolonged use, the attachment withthe cleansing implement therein received can be pulled off the handlesection, and a new attachment with a new cleansing implement can besubstituted. During such replacement, the user has no contact with thecleansing implement itself, but rather, can simply exchange it togetherwith the attachment. However, the possibility may also be provided topush the attachment onto the handle section separate from the cleansingimplement, requiring only the cleansing implement itself to be exchangedfollowing use or wear.

In a feature of the present invention, the attachment has at the endremote from the handle section a guide tube in which the free end of thecleansing implement remote from the handle section is guided. When thecleansing implement is in the extended position relative to theattachment, the cleansing implement is located in position by the guidetube. This thus reliably prevents slippage or any other variation of theposition of the cleansing implement during use.

In this arrangement, it will be advantageous to provide the guide tubewith an approximately hemispherical rounded portion at its free endremote from the handle section, preferably with a diameter in the rangefrom about 1 mm to about 4 mm, in particular about 2.5 mm. This roundedportion at the free end of the guide tube makes it easy for the user toprobe the interproximal spaces, the rounded portion, when engagingagainst the teeth, being readily locatable centrally in the recessesexisting in the region of the interproximal spaces. The * user, uponpositioning the guide tube in the region of an interproximal space inthis manner, may then slide the cleansing implement out of theattachment, inserting it in the interproximal space. Advantageously, theguide tube extends with its other end to the conical surface of thehandle section, so that all parts coming into contact with the oralcavity are interchangeable if so desired, making the device suitable foruse by several users, for example.

In a further feature of the present invention, the guide tube includes abent portion, with the bending angle being in the range from about 30degrees to about 150 degrees, in particular about 90 degrees. Thisfacilitates the manipulation of the dental cleansing device as the userprobes the interproximal spaces and introduces the cleansing implementtherein for subsequently performing the cleaning operation.

In another feature of the present invention, the attachment is providedwith means for releasably locating the cleansing implement in a transitposition in which the cleansing implement is completely received withinthe attachment. In this transit position, the attachment with thecleansing implement therein received can be handled independently of thehandle section and offered for sale, for example. Securing the cleansingimplement in the transit position prevents the cleansing implement fromaccidentally slipping within the attachment and being damaged in theprocess.

It will be advantageous in this arrangement to provide the attachmentwith a sleeve-shaped portion having an inwardly projecting annularcollar, and to provide the cleansing implement, at its end close to thehandle section, with a disk-shaped base which includes an annular grooveoperatively associated with the annular collar and adapted for lockingengagement with the annular collar to provide the transit position. Bymeans of the annular collar and the annular groove, the cleansingimplement is securely located in the transit position at lowconstructional expenditure.

In an extremely advantageous independent further feature of the presentinvention, the cleansing implement has at its end close to the handlesection means for providing a releasable coupling to a drive shaft in anon-rotating relationship thereto, the drive shaft being adapted to bedriven by a motor housed in the handle section. In this manner, thecleansing implement can be caused to rotate about its longitudinal axis.However, the non-rotative coupling does not connect the cleansingimplement with the drive shaft inseparably, but rather, the cleansingimplement can be pulled off the drive shaft. As a result, the attachmentwith the cleansing implement received therein is fully functional inpushedon condition without further means, and it can be pulled off thehandle section and replaced as a whole, for example.

It will be an advantage in this arrangement to provide the cleansingimplement and the drive shaft with a pin and an associated bore formingin assembled condition a press fit or having relatively associatedcomplementary cross-sections. Such a simple structural approach providesthe non-rotative coupling between the cleansing implement and the driveshaft.

In an advantageous feature of the present invention, the drive shaft iscoupled to a longitudinally slidable switch for energizing anddeenergizing the motor, such that a displacement of the switch alsoinvolves a displacement of the drive shaft in the longitudinaldirection, whilst, however, rotation of the drive shaft is independentof the position of the switch. Accordingly, when the user moves theswitch from the off-position to the on-position, this has at the sametime the effect of displacing the drive shaft in the longitudinaldirection. Because the cleansing implement is coupled to the driveshaft, also the cleansing implement will be displaced in thelongitudinal direction. Thus, actuation of the switch will cause thecleansing implement to be extended from the attachment. Simultaneouslywith the extension of the cleansing implement from the attachment, theswitch will also energize the motor, so that the cleansing implement,through its non-rotative coupling to the drive shaft, will be caused torotate about its longitudinal axis. With the dental cleansing device inthe activated position, the user can then clean the interproximal spacesusing the extended and rotating cleansing implement. The attendantenergization of the motor as the cleansing implement is extended fromthe attachment has the advantage of enabling the user to introduce thecleansing implement into the interproximal spaces to be cleaned withgreater ease. This introduction will be still further supported by thethreading effect produced by the rotating cleansing implement. When theuser returns the switch to the off-position, this will have the effectof retracting the cleansing implement into the attachment and stoppingits rotation.

It proves to be a great advantage that the switch for energizing themotor is slidable against a spring. As a result, the spring willautomatically return the activated dental cleansing device to theoff-condition should the user release the switch for whatever reason.This may occur, for instance, when the cleansing implement causes painresulting from improper handling by its user. The spring will promptlyact to deenergize the motor, pushing at the same time the cleansingimplement back into the attachment. This protects the user from thepossibility of pain or injury that may result from improper handling ofthe cleansing implement. The spring also ensures that the cleansingimplement is outside the attachment only during the actual cleansingoperation, being at all other times received inside the attachment inprotected manner.

From a structural point of view it will be an advantage in thisarrangement when, with the switch in the off-position, the drive shaftis in an inoperative position retracted relative to the attachment, inwhich position the cleansing implement coupled to the drive shaft isreceived inside the attachment. By contrast, with the switch in anon-position, the drive shaft is conveniently in an operative positionextended relative to the attachment, in which position the cleansingimplement coupled to the drive shaft is at least in part outside theattachment.

When in the operative position, it has proven to be particularlyadvantageous if a length in the range of about 8 mm to about 20 mm, inparticular a length of about 12 mm, of the cleansing implement isoutside the attachment. When the cleansing implement is pushed out ofthe attachment by about such a length, an optimum interproximalcleansing function can be performed.

In a further advantageous feature of the present invention, the motorfixedly accommodated in the handle section has a motor shaft withlongitudinally extending vanes, and the drive shaft has at its end closeto the motor a cup-shaped receptacle with longitudinal ribs in itsinterior, with the vanes of the motor shaft engaging longitudinally inthe space between the longitudinal ribs of the cup-shaped receptacle inan overlapping fashion. As a result, the non-rotative connection betweenthe motor shaft and the drive shaft is independent of the position ofthe drive shaft relative to the longitudinal direction. By means of thevanes and the longitudinal ribs, the rotary motion of the motor is thustransmitted from the motor shaft to the drive shaft. When the driveshaft is displaced in the longitudinal direction by means of the switch,the overlapping arrangement of the vanes and the longitudinal ribs inthe longitudinal direction ensures continued interengagement of thevanes and the longitudinal ribs, so that transmission of the rotarymotion from the motor shaft to the drive shaft is maintained at allevents. The position of the switch and thus the position of the driveshaft in the longitudinal direction accordingly does not affect thenon-rotative coupling of the motor shaft to the drive shaft.

According to an extremely advantageous, independent further aspect ofthe present invention, the attachment has at its end close to the handlesection means for releasably locating the attachment in position on thehandle section. In this manner, the attachment pushfitted to the handlesection is securely held in place. When the user desires to separate theattachment from the handle section in order to replace, for example, aworn cleansing implement, this is still possible in a ready and simplemanner.

In a feature of the present invention, the handle section and theattachment include at least one projecting lug and one associated recesswhich are in relative engagement with the attachment fitted.Conveniently, the lug is provided on the handle section, while therecess is provided on the inside of the attachment. It is, however, alsopossible to provide the lug on the attachment and the recess on thehandle section. The lug and the recess ensure secure location of theattachment on the handle section at low constructional expenditure. Bysuitably flattening the lug in particular in the push-on and pull-offdirection of the attachment, fitting and removing the attachment isfurther facilitated for its user.

Advantageously, the lug is associated with an opening extending throughthe attachment. This opening makes it easy for the user to check whetherthe lug is in proper locking engagement with the opening so that theattachment is completely fitted to the handle section.

In a further feature of the present invention, the attachment has at itsend close the handle section means for aligning the attachment in aclearly defined position to the handle section in the circumferentialdirection. In this manner, the attachment, when fitted to the handlesection, is located in a clearly defined position in the circumferentialdirection. Also, the possibility of the attachment turning on the handlesection in the circumferential direction is prevented. Operation andmanipulation of the dental cleansing device is thereby furtherfacilitated and improved for the user.

In an advantageous feature of the present invention, the handle sectionand the attachment include at least one longitudinal ridge and oneassociated longitudinal groove which are in relative engagement with theattachment fitted. Conveniently, the longitudinal ridge is provided onthe handle section, while the longitudinal groove is formed on theattachment. The reverse case is, however, also possible. Thelongitudinal ridge and the longitudinal groove afford simpleconstructional means for locating the attachment in a clearly definedposition on the handle section in circumferential direction.

Still further, it will be an advantage to provide one longitudinal ridgeand one longitudinal groove each on either side of the lug and recess,respectively. The arrangement of two longitudinal ridges andlongitudinal grooves further facilitates the insertion of the attachmentin the handle section for the user. The symmetrical arrangement of thelongitudinal ridges and longitudinal grooves affords the furtheradvantage of providing the dental cleansing device with a visuallybalanced appearance.

In still another feature of the present invention, three lugs andrecesses, respectively, with associated longitudinal ridges andlongitudinal grooves, respectively, are provided, which are arranged onthe periphery of the handle section and, respectively, the attachment atpartly non-uniform distances. As a result of this arrangement, thevisual impression conveyed makes it easier for the user to properly fitthe attachment to the handle section without further thinking. Thelocation of the attachment on the handle section is thus visuallyexpressed by the non-uniform arrangement.

Further features, advantages and application possibilities of thepresent invention will become apparent from the subsequent descriptionof embodiments illustrated in more detail in the accompanying drawings.It will be understood that all features described and/or represented byillustration, whether taken alone or in any desired combination,constitute the subject-matter of the present invention, irrespective oftheir summarization in the claims and their back-references.

In the drawings,

FIG. 1 is a perspective view of a dental cleansing device showing thecleansing implement in attached condition;

FIG. 2 is a view on an enlarged scale of the cleansing implement of FIG.1;

FIG. 3 is a cross-sectional view of the cleansing implement of FIG. 2,taken along the line III of FIG. 4;

FIG. 4 is a side view of the cleansing implement of FIG. 2, as seenlooking from the direction IV of FIG. 3;

FIG. 5 is a schematic side view, partly in section, of an embodiment ofa dental cleansing device of the present invention;

FIG. 6 is a schematic view, partly in section and on an enlarged scale,of the attachment fitted to the handle section of the dental cleansingdevice in the inoperative position;

FIG. 7 a schematic view, partly in section and on an enlarged scale, ofthe attachment fitted to the handle section of the dental cleansingdevice in the operative position;

FIG. 8 is a schematic view, partly in section and on an enlarged scale,of the attachment in the transit position;

FIG. 9 is a schematic view, partly in section and on an enlarged scale,of the area in which the attachment is fitted to the handle section;

FIG. 10 is a schematic cross-sectional view of the attachment takenalong the line A--A of FIG. 9; and

FIG. 11 is a schematic cross-sectional view of the handle section takenalong the line A--A of FIG. 9.

FIG. 1 shows a dental cleansing device 1 with a cleansing implement 32attached. The dental cleansing device 1 includes a handle section 2receiving an electric motor drive means adapted to be turned on and offby the user. Adjoining the handle section 2 is a mounting section 101serving the function of transmitting and, where applicable, converting,the rotary motion produced by the electric motor drive means. Thecleansing implement 32 is attachable to the head end of the mountingsection 101. In FIG. 1, the cleansing implement 32 is arranged at thefree end of the mounting section at an angle of about 90 degrees to thelongitudinal axis of the mounting section 101 and the handle section 2.It is, however, also possible to arrange the cleansing implement 32 inthe direction of the longitudinal axis of the mounting section 101 andthe handle section 2 or to provide for adjustability between thesepositions. The cleansing implement 32 is attached to the free end of themounting section 101 in such a manner as to be rotatable about itslongitudinal axis by the electric motor drive means of the dentalcleansing device 1. The rotational frequency may be about 3,000 1/min orhigher, for example.

The cleansing implement 32 will be explained in greater detail in thefollowing with reference to FIGS. 2 to 4.

The cleansing implement 32 of FIG. 2 is comprised of a mounting shaft122 and a cleansing shaft 125, with the mounting shaft 122 with itsdiameter of about 1.5 mm being significantly thicker than the cleansingshaft 125 with a mean diameter of about 0.3 mm. By means of the mountingshaft 122 the cleansing implement 32 is attached to the free end of themounting section 101 of the dental cleansing device 1. In FIG. 2, themounting shaft 122 is of a cylindrical configuration, but it is alsopossible to provide the mounting shaft 122 with a differentcross-sectional area, or to provide the mounting shaft 122 withadditional longitudinal grooves or longitudinal ribs for non-rotativeconnection of the cleansing implement 32 with the electric motor drivemeans of the dental cleansing device 1. Through a transition area, thecleansing shaft 125 is connected with the mounting shaft 122 and servesto clean the teeth. The cleansing shaft 125 of FIG. 2 has a length d ofabout 12 mm and a thickness of between 0.3 and 0.4 mm±0.1 mm, which isthus substantially smaller than its length.

As becomes apparent from FIG. 3, the cleansing shaft 125 has a squarecross-sectional area. The four corners of this square cross-sectionalarea form longitudinal edges 126 extending substantially along the fulllength d of the cleansing shaft 125. The cross-sectional length a of thesquare cross-section is about 0.3 mm.

A plurality of projecting serrations 127 are provided on the surface ofthe cleansing shaft 125, that is, on the surface bounded by thelongitudinal edges 126, as illustrated schematically in FIG. 4. Theheight b of these serrations 127 is about 0.2 mm. The width c of a tooth127 thereof is equally about 0.2 mm. Starting from a broad base on thesurface of the cleansing shaft 125, the serrations 127 are taperedtowards a pointed end. The taper angle e of the serrations 127 is about90 degrees.

One end of the cleansing shaft 125 is advantageously provided with anessentially blunt, rounded portion 128 whose radius may be 0.2 mm, forexample. This facilitates insertion of the cleansing implement into theinterproximal spaces.

The complete cleansing implement 32 comprised of mounting shaft 122 andcleansing shaft 125 is configured as an integral component made of aplastics material and suitable for manufacture by injection molding. Itwill be particularly advantageous to use a plastic fiber with propertiessimilar to that of dental floss. Further, greater ease of manufacture ofthe cleansing implement 32 is obtained by using a plastics material withgood flow properties.

In use of the cleansing implement 32, it is particularly by means of thelongitudinal edges 126 that plaque is wiped of f the teeth. Theserrations 127 serve to loosen the plaque bacteria from the teeth. Itwill be understood that the cleansing implement 32 is also suitable forremoving food particles from the teeth. The thin and elongateconfiguration of the cleansing implement 32 also enables tightinterproximal spaces to be cleaned.

Because of the high rotational frequency of the cleansing implement 32of about 3,000 1/min or higher, the flexible cleansing shaft 125 threadsitself automatically into the interproximal spaces to be cleaned, alsoin cases where the user fails to position the dental cleansing device 1accurately, which is a frequent occurrence particularly at inaccessiblelocations of a person's teeth. Moreover, the high rotational frequencyof the cleansing implement 32 provides for rapid and thorough removal ofplaque, being thus superior to conventional interproximal cleaninginstruments as, for example, hand-operated toothpicks.

The cleansing shaft 125 or the complete cleansing implement 32 ispreferably made of polyester elastomer, enabling the cleansing shaft 125to be bent also during use by an angle of up to 180 degrees whilerotating at a frequency of about 3,000 1/min±2,000 1/min.

FIG. 5 shows a dental cleansing device 1 which is composed of a handlesection 2 and an attachment 3 fitted thereto. The handle section 2 is ofan elongate configuration with a circular cross-section. A portion 4 ofthe handle section 2 at the end close to the attachment 3 is of areduced diameter compared to a portion 5 of the handle section 2 at theend remote from the attachment 3. The attachment 3 is equally of anessentially elongate configuration with a circular cross-section. Thediameter of a portion 6 of the attachment 3 at the end close to thehandle section 2 corresponds to the diameter of the portion 4 of thehandle section 2. At the end remote from the handle section 2, theattachment 3 is provided with a guide tube 7 of a reduced diameter whichincludes a bent portion 8.

Fixedly mounted in the portion 5 of the handle section 2 is anelectrically powered motor 9 connected to a voltage source 12, inparticular a rechargeable accumulator, via an electric conductor 10. Alongitudinally slidable switch 13 is equally housed in the portion 5 ofthe handle section 2. Provided on the switch 13 is an electricallyconductive contact means 14 which in turn is e connected to the voltagesource 12 via an electric conductor 11. The switch 13 further includes acoupling member 15 serving to couple the switch 13 to a drive shaft 16.

The drive shaft 16 extends through the entire portion 4 into the portion5 of the handle section 2 and has at its free end close to the motor 9in the area of the handle section 2 a cup-shaped receptacle 17 with anopening 18. The motor 9, the drive shaft 16 and the cup-shapedreceptacle 17 are concentrically arranged with a common axis 19, withthe opening 18 of the cup-shaped receptacle 17 being provided at the endclose to the motor 9.

Projecting outwardly from the radial outside of the cup-shapedreceptacle 17 are two relatively spaced annular collars 20, 21 definingan annular groove 22 therebetween for engagement by an annular collar 23projecting inwardly from the coupling member 15. In this arrangement,the annular collar 23 engages with the annular groove 22 in such amanner that a displacement of the switch 13 in the longitudinaldirection results at the same time in a displacement of the cup-shapedreceptacle 17 likewise in the longitudinal direction. While the annularcollar 23 is stationary in the circumferential direction, the cup-shapedreceptacle 17 with its annular groove 22 is rotatable about the annularcollar 23. The cup-shaped receptacle 17 is thus capable of rotatingabout the axis 19 irrespective of the position of the switch 13. It willbe understood that a bearing or the like, not shown, may be arrangedadditionally in the area of the annular collar 23 and the associatedannular groove 22, by means of which friction between the annular collar23 and the annular groove 22 can be reduced, thereby facilitating therotary motion of the cup-shaped receptacle 17 about the axis 19.

At the end of the cup-shaped receptacle 17 close to the opening 18, amotor shaft 24 extends from the motor 9, the shaft being arrangedconcentrically with the axis 19 as is the motor 9. The motor shaft 24 isprovided with at least one, preferably however, three vanes 25projecting radially outwardly from the motor shaft 24 and extending inthe longitudinal direction. The cup-shaped receptacle 17 has in itsinterior a corresponding number of longitudinal ribs 26 projectingradially inwardly and extending likewise in the longitudinal direction.The vanes 25 extend through the opening 18 into the interior of thecup-shaped receptacle 17, engaging in the space between the longitudinalribs 26. In this arrangement, the vanes 25 and the longitudinal ribs 26overlap longitudinally along a length which is greater than the maximumlength of displacement of the switch 13 in the longitudinal direction.

The vanes 25 and the longitudinal ribs 26 provide for transmission ofthe rotary motion of the motor shaft 24 to the cup-shaped receptacle 17and thus to the drive shaft 16. The overlapping arrangement of the vanes25 and the longitudinal ribs 26 in the longitudinal direction enablesthe cup-shaped receptacle 17 to be displaced by means of the switch,without the transmission of the rotary motion of the motor shaft 24 tothe drive shaft 16 being affected thereby. It will be understood thatthis coupling structure between the motor shaft 24 and the drive shaft16 by means of the vanes 25 and the longitudinal ribs 26 may also beconfigured in a different manner, providing, for example, a suitablegearing or the like.

Seated between the side of the annular collar 20 facing the portion 4 ofthe handle section 2 and the transition area between the portion 5 andthe portion 4 of the handle section 2 is a spring 27 which is located inposition by means of support walls 28, 29. The spring 27 produces aforce acting in opposition to a displacement of the switch 13 towardsthe attachment 3. As a result, the spring 27 invariably urges the switch13 and thus the drive shaft 16 automatically into a direction away fromthe attachment 3 without any external influence.

As described in the foregoing, the drive shaft 16 extends along the fulllength of the portion 4 of the handle section 2. At the end of thehandle section 2 close to the attachment 3, the drive shaft 16 is guidedby an annular collar 30 projecting inwardly from the handle section 2.Further, the drive shaft 16 projects at this end from the handle section2 by a small amount, its free end being provided with a bore 31extending concentrically with the axis 19.

In the attachment 3 fitted to the handle section 2, a cleansingimplement 32 is longitudinally slidably received. The cleansingimplement 32 includes a cleansing shaft 33 of an elongate and thinconfiguration. Preferably, the cleansing shaft 33 is about 30 mm longwith a diameter of about 0.5 mm. The cleansing shaft 33 is made of aplastics material, in particular a polyester elastomer as, for example,HYTREL™. The cleansing shaft 33 is flexible, allowing bending by anangle of up to 150 degrees, minimum, also as it rotates about itslongitudinal axis.

At its end close to the drive shaft 16, the cleansing implement 32includes a circular base 34 connected to the cleansing shaft 33, as wellas a pin 35 connected to the base 34. The pin 35 of the cleansingimplement 32 is received in the bore 31 of the drive shaft 16. The pin35 and the bore 31 may press-fitted together or, alternatively, thecross-sectional shapes of the pin 35 and the bore 31 may be conformed toeach other, for example, in the form of a polygon or the like.

As set forth previously, the attachment 3 is fitted to the handlesection 2. Further, the pin 35 is inserted in the bore 31 in anon-rotating relationship thereto. The cleansing shaft 33 extends fromthe base 34 to the guide tube 7 and is then passed through the guidetube 7.

Because of the bent portion 8 of the guide tube 7, the cleansing shaft33 includes likewise a correspondingly bent portion 36. In the Figures,an angle of about 90 degrees is provided for the bent portions 8 and 36.It will be understood that the bent portions 8 and 36 may also be bentat different angles, particularly at angles in the range from about 30degrees to about 150 degrees.

The free end of the guide tube 7 is provided with an essentiallyhemispherical rounded portion 37. The diameter of this rounded portion37 amounts to a value in the range from about 1 mm to about 4 mm, inparticular a value of about 2.5 mm.

The dental cleansing device 1 illustrated in FIG. 5 provides two modes,an off-mode in which the cleansing implement 32 is in the inoperativeposition, and an onmode in which the cleansing implement 32 is in theoperative position. FIG. 5 shows the cleansing implement 32 in both theinoperative and the operative position, illustrating the base 34 and thepin 35 of the cleansing implement 32 twice, once for each position.However, the drive shaft 16 and the other parts of the dental cleansingdevice 1 are all shown in the off-mode and thus in their inoperativepositions.

FIGS. 6 and 7 are provided for a better understanding of the on andoff-modes with the related operative and inoperative positions. FIG. 6shows the cleansing implement 32 in the inoperative position, while FIG.7 shows the operative position thereof. In the subsequent description,reference will be preferably made first to the two last-mentioned FIGS.6 and 7, while for the explanation of the mode of function FIG. 5 willbe referred to preferably.

In the inoperative position shown in FIG. 6, the cleansing implement 32and in particular the cleansing shaft 33 are fully received in theinterior of the attachment 3. The base 34 and the pin 35 are in theimmediate proximity of the end of the handle section 2 close to theattachment 3. In contrast thereto, in the operative position shown inFIG. 7, the cleansing implement 32 is not fully received inside theattachment 3. The free end of the cleansing shaft 33 projects from thefree end of the guide tube 7. Preferably, the cleansing shaft 33projects from the guide tube 7 with a length of about 10 mm to about 15mm, in particular about 12 mm. This is accomplished by longitudinaldisplacement of the base 34 and the pin 35 of the cleansing implement 32away from the handle section 2. The base 34 and the pin 35 are then nolonger in the proximity of the handle section 2, but rather,approximately in the transition area between the portion 6 of theattachment 3 and the guide tube 7. The base 34 and the pin 35 aredisplaced within the attachment 3 by a length corresponding precisely tothe amount by which the cleansing shaft 33 projects from the guide tube7.

In the inoperative position the switch 13 is in its off-position asshown in FIG. 5. The contact means 14 is not in electrical contact withthe electrically conductive surface of the motor 9. The motor 9 isaccordingly off. The motor shaft 24 and thus the drive shaft 16 and thecleansing implement 32 do not rotate. Due to the position of the switch13 and the force exerted by the spring 27 on the cup-shaped receptacle17, also the drive shaft 16 is in the inoperative position illustratedin FIG. 5. As a result, the retracted position of the drive shaft 16towards the motor 9 also causes the cleansing implement 32 to be in itsinoperative position illustrated in FIG. 6, in which in particular thecleansing shaft is fully received in the interior of the attachment 3.

When a user then shifts the switch 13 in the longitudinal directiontowards the attachment 3, the contact means 14 will contact theelectrically conductive surface of the motor 9. The circuit forenergization of the motor 9 will thereby be closed via the conductor 10the voltage source 12, the contact means 14, and the conductor 11. Themotor shaft 24 will thus be caused to rotate about the axis 19. By meansof the vanes 25 and the longitudinal ribs 26, this rotary motion will betransmitted to the drive shaft 16. Via the bore 31 and the pin 35, therotary motion will then be transmitted to the cleansing implement 32,causing the cleansing shaft 33 to rotate about its own axis partlyrectilinearly and partly along its bent portion 36.

Displacement of the switch 13 by the user results at the same time in adisplacement of the drive shaft 16 in the same direction through theannular collar 23 and the annular groove 22. This motion is transmittedto the cleansing implement 32 via the bore 31 and the pin 35. As aresult, the cleansing shaft 33 moves from its inoperative position awayfrom the handle section 2 in the direction of its operative positionillustrated in FIG. 7. When the switch 13 has completed its displacementtravel to its maximum permissible on-position, the amount of extensionof the cleansing shaft from the guide tube is at its maximum, as shownin FIG. 7. The rotating and fully extended cleansing shaft 33 thenenables the user to clean the interproximal spaces.

When the user releases the switch 13, it will be shifted back to itsoff-position by the force of the spring 27. This will also cause thecleansing implement 32 to return to its inoperative position. At thesame time, the contact means 14 will stop contacting the motor 9,causing the motor 9 to be off. The dental cleansing device 1 is again inthe off-condition previously explained.

FIG. 8 shows the attachment 3 with the cleansing implement 32 receivedtherein as a separate part, that is, detached from the handle section 2.The attachment 3 has about centrally in its portion 6 an inwardlyprojecting annular collar 38. Further, the circular base 34 of thecleansing implement 32 is provided with an annular groove 39 conformedto the annular collar 38. In the transit position of the cleansingimplement 32 shown in FIG. 8, the annular groove 39 is in lockingengagement with the annular collar 38. This securely captures thecleansing implement 32 inside the attachment 3. The annular collar 38and the annular groove 39 are arranged such that in the transit positiondescribed the cleansing implement 32 is fully received within theattachment 3.

When the attachment 3, with the cleansing implement 32 in lockingengagement therewith, is fitted to the handle section 2, this has theattendant effect of inserting the pin 35 into the bore 31. Shortlybefore the attachment 3 is completely push-fitted to the handle section2, the annular collar 38 will be disengaged from the annular groove 39,so that the cleansing implement 32, rather than being held captiveinside the attachment 3, will then be coupled to the drive shaft 16through the pin 35 and the bore 31.

When the attachment 3 is withdrawn from the handle section 2, the base34 will abut the annular collar 38, causing the pin 35 of the cleansingimplement 32 to be pulled out of the bore 31. The cleansing implement 32will not remain coupled to the drive shaft 16, but rather, it will bepulled off together with the attachment 3.

Referring to FIGS. 9 to 11, it will now be explained how the attachment3 is fitted to the handle section 2. As shown, the attachment 3 includesthree openings 40, 41 and 42 spaced at an angle of about 90 degrees onthe periphery of the attachment 3. In the absence of a fourth opening,the three openings 40, 41 and 42 provided are partly non-uniformlyspaced on the periphery of the attachment 3. Each of the openings 40, 41and 42 is associated with a respective lug 43, 44 and 45 projectingapproximately radially outwardly from the handle section 2.

In the area of overlap with the handle section 2, the attachment 3 hasan increased diameter to enable the lugs 43, 44 and 45 of the handlesection 2 to engage the respective openings 40, 41 and 42 of theattachment 3. This is illustrated in FIG. 9. The lugs 43, 44 and 45 areof a flattened configuration in the longitudinal direction, thusenabling the user to insert and withdraw the handle section 2 in andfrom the attachment 3 without major effort. In the locked conditionillustrated in FIG. 9, the lugs 43, 44 and 45 engaging the respectiveopenings 40, 41 and 42 are visible to the eye.

As appears particularly from FIG. 10 showing a cross-sectional view ofthe attachment 3, each of the openings 40, 41 and 42 is associated witha respective pair of longitudinal grooves 46, 47 and 48.Correspondingly, each of the lugs 43, 44 and 45 is associated with arespective pair of longitudinal ridges 49, 50, 51, as becomes apparentparticularly from FIG. 11 showing a cross-sectional view of the handlesection 2. When viewed in the circumferential direction, onelongitudinal groove is provided on either side of the openings 40, 41and 42, and one longitudinal ridge is provided on either side of thelugs 43, 44 and 45. The longitudinal grooves 46, 47 and 48 and thelongitudinal ridges 49, 50 and 51 are conformed to each other such as tobe in relative engagement when the attachment 3 is fitted to the handlesection 2, the longitudinal ridges 49, 50 and 51 then sliding alonginside the longitudinal grooves 46, 47 and 48.

By means of in particular the longitudinal grooves 46, 47 and 48 and thelongitudinal ridges 49, 50 and 51, the attachment 3 is located in aclearly defined position on the handle section 2 in the circumferentialdirection. Obviously, not all of the longitudinal ridges, longitudinalgrooves, openings and lugs may be necessary for such a location. In thesimplest case, a single lug will suffice which engages an associatedthrough opening or a non through-going recess, thereby locating theattachment 3 in a clearly defined position on the handle section 2 inthe circumferential direction. Equally obviously, such a location canalso be accomplished by means of other structural arrangements.

What is claimed is:
 1. An electrically powered dental cleansing devicecomprising:a handle section having a drive shaft received therein; acleansing implement configured to be coupled to the drive shaft and tobe set in rotation by the drive shaft about its longitudinal axis; andan attachment, wherein the cleansing implement is slidably and rotatablyreceived in the attachment which is adapted to be push-fitted to thehandle section.
 2. The electrically powered dental cleansing device asclaimed in claim 1, wherein the attachment includes at an end remotefrom the handle section a guide tube in which a free end of thecleansing implement remote from the handle section is guided.
 3. Theelectrically powered dental cleansing device as claimed in claim 2,wherein the guide tube is provided with an approximately hemisphericalrounded portion at its free end remote from the handle section, with adiameter in the range from about 1 mm to about 4 mm.
 4. The electricallypowered dental cleansing device as claimed in claim 2, wherein the guidetube is provided with an approximately hemispherical rounded portion atits free end remote from the handle section, with a diameter of about2.5 mm.
 5. The electrically powered dental cleansing device as claimedin claim 2, wherein the guide tube of the attachment includes a bentportion, with a bending angle in the range from about 30 degrees toabout 150 degrees.
 6. The electrically powered dental cleansing deviceas claimed in claim 2, wherein the guide tube of the attachment includesa bent portion, with a bending angle of about 90 degrees.
 7. Theelectrically powered dental cleansing device as claimed in claim 1,wherein the attachment includes an annular collar configured toreleasably locate the cleansing implement in a transit position in whichthe cleansing implement is completely received within the attachment. 8.The electrically powered dental cleansing device as claimed in claim 1,wherein the attachment includes a sleeve-shaped portion having aninwardly projecting annular collar, and the cleansing implement, at itsend closest to the handle section, includes a disk-shaped base having anannular groove operatively associated with the annular collar andadapted to lockingly engage with the annular collar to provide a transitposition of the cleansing implement.
 9. The electrically powered dentalcleansing device as claimed in claim 1, wherein the cleansing implementincludes at its end close to the handle section a pin configured tocouple to the drive shaft in an non-rotating relationship thereto, saiddrive shaft configured to be driven by a motor housed in the handlesection.
 10. The electrically powered dental cleansing device as claimedin claim 1,wherein the cleansing implement includes a pin and the driveshaft includes a bore, said pin and said bore having relativelyassociated complementary cross-sections which in assembled conditionform a press-fit.
 11. The electrically powered dental cleansing deviceas claimed in claim 1, wherein the attachment includes at its endclosest to the handle section at least one recess configured toreleasably locate the attachment in position on the handle section. 12.The electrically powered dental cleansing device as claimed in claim 1,wherein the handle section and the attachment include at least oneprojecting lug and one associated recess which are in relativeengagement with the attachment push-fitted onto the handle section. 13.The electrically powered dental cleansing device as claimed in claim 12,wherein the lug is associated with an opening extending through theattachment.
 14. The electrically powered dental cleansing device asclaimed in claim 11, wherein the attachment includes at its end closestto the handle section a longitudinal groove for aligning the attachmentin a clearly defined position in the circumferential direction relativeto the handle section.
 15. The electrically powered dental cleansingdevice as claimed in claim 11, wherein the handle section and theattachment include at least one longitudinal ridge and one associatedlongitudinal groove which are in relative engagement with the attachmentpush-fitted onto the handle section.
 16. The electrically powered dentalcleansing device as claimed in claim 15, wherein the handle section andthe attachment include at least one projecting lug and one associatedrecess which are in relative engagement with the attachment push-fittedonto the handle section; and wherein one longitudinal ridge and onelongitudinal groove each are provided on either side of the lug and therecess, respectively.
 17. The electrically powered dental cleansingdevice as claimed in claim 16, wherein the handle section and theattachment include three lugs and recesses, respectively, withassociated longitudinal ridges and longitudinal grooves, respectively,arranged with at least partly non-uniform distances on the periphery ofthe handle section and, respectively, of the attachment.
 18. Theelectrically powered dental cleansing device as claimed in claim 1,wherein the cleansing implement is an integrally formed part, includinga cleansing shaft which is flexible and made of a polyester elastomer ora material of similar flexural strength, and can be set in rotation by amotor of the dental cleansing device.
 19. The electrically powereddental cleansing device as claimed in claim 18, wherein the cleansingshaft includes at least one longitudinal edge.
 20. The electricallypowered dental cleansing device as claimed in claim 18, wherein thecleansing shaft has an essentially square cross-section.
 21. Theelectrically powered dental cleansing device as claimed in claim 20,wherein a side of the square cross-section has a length of approximately0.3 mm.
 22. The electrically powered dental cleansing device as claimedin claim 18, wherein a plurality of serrations project from a surface ofthe cleansing shaft.
 23. The electrically powered dental cleansingdevice as claimed in claim 22, wherein each serration has a height ofapproximately 0.2 mm.
 24. The electrically powered dental cleansingdevice as claimed in claim 23, wherein each serration has a width ofapproximately 0.2 mm.
 25. The electrically powered dental cleansingdevice as claimed in claim 18, wherein the cleansing shaft is integrallyformed having an unbalanced structure.
 26. The electrically powereddental cleansing device as claimed in claim 18, wherein the cleansingshaft has a length of 12 mm.
 27. The electrically powered dentalcleansing device as claimed in claim 18, wherein the cleansing implementis made of Hytrel®.
 28. The electrically powered dental cleansing deviceas claimed in claim 18, wherein the cleansing implement is configured tobe a push-fit on the dental cleansing device.
 29. The electricallypowered dental cleansing device as claimed in claim 18, wherein thecleansing shaft includes at one end a blunt rounded portion.
 30. Theelectrically powered dental cleansing device as claimed in claim 18,wherein the cleansing shaft is thin and elongate.
 31. An electricallypowered dental cleansing device comprising:a handle section including adrive shaft, a motor coupled to a drive shaft, and a switch to which thedrive shaft is coupled and which is for energizing and de-energizing themotor, wherein a displacement of the switch also effects a displacementof the drive shaft in a longitudinal direction relative to the driveshaft; a cleansing implement configured to be coupled to the drive shaftand to be set in rotation about its longitudinal axis; and an attachmentin which the cleansing implement is slidably and rotatably received andwhich is adapted to be push-fitted to the handle section.
 32. Theelectrically powered dental cleansing device of claim 31 wherein theswitch is slidable in the longitudinal direction of the handle section.33. The electrically powered dental cleansing device as claimed in claim31, wherein the switch for energizing the motor is slidable against aspring.
 34. The electrically powered dental cleansing device as claimedin claim 31, wherein in the off-position of the switch the drive shaftis in an inoperative position retracted relative to the attachment, inwhich position the cleansing implement connected to the drive shaft isreceived inside the attachment.
 35. The electrically powered dentalcleansing device as claimed in claim 31, wherein in an on-position ofthe switch the drive shaft is in an operative position extended relativeto the attachment, in which position the cleansing implement connectedto the drive shaft is at least in part outside the attachment.
 36. Theelectrically powered dental cleansing device as claimed in claim 35,wherein a length in the range of about 8 mm to about 20 mm of thecleansing implement is outside the attachment.
 37. The electricallypowered dental cleansing device as claimed in claim 35, wherein a lengthof about 12 mm of the cleansing implement is outside the attachment. 38.The electrically powered dental cleansing device as claimed in claim 31,wherein the motor is fixedly accommodated in the handle section andincludes a motor shaft having longitudinally extending vanes, and thedrive shaft includes at its end closest to the motor a cup-shapedreceptacle having longitudinal ribs in its interior, wherein the vanesof the motor shaft overlappingly and longitudinally engage the spacebetween the longitudinal ribs of the cup-shaped receptacle.